The invention described herein relates to the packaging of electronic processing components in a computer system, and more specifically to an apparatus which provides for high density packaging of electronic processing components where the electronic assemblies are relatively simple to construct.
As airplane and spacecraft have become more technologically sophisticated, there has been a greater need to include more electronic components on the vehicles. For example, avionics systems which are employed to control the flight and other aspects of the aircraft and/or spacecraft, require a great number of electronic processing components, as well as input/output and interconnected signal lines so that the various components may communicate.
Typically, an aircraft or spacecraft will carry a number of xe2x80x9cblack boxesxe2x80x9d which includes circuit cards designed to perform particular functions. A number of circuit cards may be positioned in each black box and soldered connections provided from each circuit card to the components with which it is to communicate. These soldered connections may be made to a motherboard, which in turn provides for communications from a particular black box with any number of remotely located systems.
The inventor has recognized that certain difficulties may exist with regards to using black boxes on platforms such as aircraft or spacecraft. These include the amount of space these components take up as well as the difficulty in manufacturing and maintaining these devices. The inventor has further recognized, that an electronic assembly may employed which performs essentially the same functions as the traditional black box but is compact and easy to fabricate and repair. In particular, the inventor has recognized that the use of certain devices which establish electrical connections through use of compressive forces instead of soldering and other traditional interconnect techniques, would be advantageous and would also save space, especially in space limited areas such as those on the vehicles described above.
The applicant""s invention includes an apparatus for providing electrical interconnections between electronic processing devices. In the invention described herein, the electronics devices may include processing components such as circuit chips. These processing devices may be packaged in an electronics module which includes at least one external electrical contact. This contact would provide for the routing of electrical signals to and from the processing devices. The apparatus described herein may further include an external signal routing device, such as a motherboard device which provides electrical connection between the electronics module and any external systems or components. This motherboard device may also include at least one exterior electrical connection.
In order to provide for electrical connection between the electronics module and the motherboard device, an interposer device may provided which include at least one conductive pathway which may route electrical signals from one component to the other. In particular, the interposer may include exposed electrical connections which pass from one side of the device to the other. One end of a conductive pathway may be placed in electrical connection with the exterior electrical contact for the electronics module, and the other end of the conductive pathway placed in electrical contact with the exterior electrical contact of the motherboard device such that electrical signals may be conducted between these components. In order to maintain the electrical connection, a compressive force may be exerted on both the motherboard device and the electronics module which in turn compresses the interposer device and its conductive pathways. While the compressive force is maintained, a conductive pathway is provided between these components.
In order to apply the compressive force, a bracket assembly may be provided in which the above described components, when placed in a stacked configuration, may be compressed together in order to establish the electrical connections. The bracket assembly may further provide for limiting any relative motion of the components to which the compressive force is being applied, in order to maintain the integrity of the electrical connections.
The electronics module may comprise a device such as a high density interconnect (HDI) module or a multi-chip module (MCM). The HDI may include a ceramic carrier which includes a number of cavities which are sized to receive a variety of submodules. The submodules may contain a variety of circuit elements, such as circuit dice, which include a processing components. Interconnections are provided within the submodules and between the submodules for communications. Included on the exterior surface of the HDI module may be a number of electrical contacts laid out in a predetermined pattern. These contacts may be made of a electrically conductive material and protrude slightly from the surface of the carrier.
The interposer device may be a relatively thin sheet of hard plastic through which a number of electrically conductive pathways may pass. The traces begin by protruding slightly from one surface of the plastic sheet, run through the thickness of the sheet, and then protrude on the other side. The conductive traces are incorporated into the interposer in a pattern such that a particular conductive trace will contact a particular electrical contact on the HDI module when these components are stacked in the electronic assembly described herein.
The motherboard device, may also include a number of external electrical contacts which are laid out in a pattern to match the conductive traces which protrude from the interposer device. The motherboard device may be a layered Kapton structure which includes a number of conductive internal circuit traces which route signals from the external electrical contacts to a remotely located devices and/or systems. The motherboard device may include rigid and flexible portions, wherein the rigid portion may be used within the assembly itself in order to establish and maintain electrical contacts, while the flexible portion may be outside the electronic assembly and is used to establish electrical connections with other devices.
The means to apply and maintain a compressive force on the components of the electronic assembly may comprise a bracket assembly. This bracket assembly may include a base frame which is configured to receive the electrical components of the assembly and provide the necessary restraints such that relative movement between the components is limited. Attachment means may also be provided in this base frame for attaching the electronic assembly to any structure in its operating environment. Also included in the base frame may be a number of holes through which connectors such as bolts may pass. In this configuration, some or all of the electronic components in this assembly include connection holes which align with the connection holes through the base frame when these items are in a stacked configuration. Alternatively, the base frame may also be configured to receive and restrain one or more electronic components without the use of connectors.
Also included in the bracket assembly may be a frame clamp which is positionable adjacent to the stacked electronic components opposite the base frame. This frame clamp may also includes connection holes which align with the connection holes through the electronic components as well as the base clamp. Once the electronic components are in a stacked configuration and the connection holes aligned, a bolt connector may be run through the frame and base clamps as well as the electronic devices, and some sort of fastener device such as a nut which threads onto the bolt may be applied and tightened down. The nuts on the connector bolts may be tightened to the point such that a desired compressive force is applied to the electrical components of the assembly. This compressive force should be sufficient to establish and maintain electrical connections, as well as limit relative movement of the components when the electronic assembly is in operation.
During the construction of the assembly, alignment pins may also be employed to further limit any relative motion between the various electronic components. Additional holes may be provided through the motherboard, interposer, and electronics module, and a specially configured hole included in the base clamp. The alignment pin may include a specially configured head at one end which is positioned in the specially configured hole in the base frame. During the fabrication of the assembly, each electronic component may be threaded onto the alignment pin and once the frame clamp is positioned and tightened down, this alignment pin may act to limit the movements of the electronic components.
Alternatively, the electronic assembly may be constructed to employ ballard pins instead of threaded bolts and nuts. In this configuration, the frame clamp is configured with special connecting hole and slot especially designed to receive a ballard pin. After the electronic components are stacked in the base clamp, and the ballard pin run through the connecting holes, the frame clamp may be placed over the ballard pins and then slid into the locking position, thus applying a compressive force to the electrical components of the assembly.
In yet another configuration, the flexible connector running from the motherboard device may be specially configured such that connections are established with a plurality of motherboards. In this configuration, connection lines for each motherboard may be routed to a common portion of the flexible connector which then provides for the routing of the electrical signals to other remotely located systems. Specially configured flexible portions may be included in the I/O connector such that this component may be shaped in a desired fashion in order to establish connection or conserve space.